Fw: [Elecraft] W1 - no autoscaling

[ON4WIX]

Hi again,

I have some more findings that may help in narrowing down the cause of my 
problem:

It seems like the W1 recognises that more power than 1,4W is being sensed 
but somehow it does not react as it
should, i.e. autoscale up to a higher power level. It just reads full scale 
when I run more than 1,4W and the display takes a long time to recover at 
key-up (+/- 1 second before the FWD PWR leds start to switch off).
I have also tested the W1 running on a 9V battery and I get the very same
results.
Furthermore, with the W1 hooked up to my PC running the Elecraft W1 software
v1.10 I get accurate power readings up to 15 watts. Anything above 15 watts
is displayed as 15 watts, period.
I checked all components around the U4 scaling section and everything seems 
fine there.
Is it possible that the PIC in this kit is corrupt? I do get accurate 
on-board readings up to 1,4 watts and
the software shows accurate readings up to 15 watts so the problem seems so
be firmware-oriented rather than a hardware problem.

Any input would be very much appreciated.

73
Glenn ON4WIX


----- Original Message ----- 
From: "ON4WIX" <on4wix at skynet.be>
To: <elecraft at mailman.qth.net>
Sent: Sunday, May 25, 2008 5:57 PM
Subject: [Elecraft] W1 - no autoscaling


> Hi all
>
> I just finished building the W1 wattmeter kit. All went fine without any 
> problems.
> The part "Checkout and Calibration" (p9 of the manual) was spot on. I have 
> 4,50V DC at TP1 and >1Meg-ohm across the battery terminals.
> First power-on test went flawlessly - The FWD leds blinked, then the SWR 
> leds, then the 1,4 / 14 / 140W scale leds.
> Then things went acting funny. Powering the W1 from my MFJ 4125 power 
> supply and running my K3 into the W1 and terminating into a known good 
> dummy load I get perfectly accurate power and SWR readings when running no 
> more than 1,4 watts. However, the W1 does not autoscale when my K3's 
> output power goes above 1,4 watts. Whichever power I run, the W1 keeps 
> showing the 1,4W green led and I get full scale FWD power readings.
> I have also tested the W1 running on a 9V battery and I get the very same 
> results.
> The manual says that U4, running FW 1.05, should take care of autoscaling. 
> but apparently there's something wrong here. The funny thing is that the 
> SWR reading seems to be fine. Using 1W, 10W and 100W show consistent SWR 
> readings.
> Any thoughts on where I should look first? As stated before, the lowest 
> power level shows perfectly accurate power/SWR readings.
>
> Thanks for any help
>
> Glenn ON4WIX
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft at mailman.qth.net
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1463 - Release 
> Date: 23/05/2008 15:36
>
>